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Presentation by:

Jesse Conklin

Group Members:

J.P. Telemaque & Mike Milano

First National Educational Competition onPredicting Progressive Collapse Resistance of

Reinforced Concrete Structural Systems

Level 1 – UndergraduateUniversity of Massachusetts Amherst

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Competition OutlineLevel 1 – Undergraduate

1/8” scale 2-D model of a RC frame with 3 stories and 4 bays 2 Step procedure:

– Instantaneously removing the glass column at first floor in the center of the frame

– If the frame remained standing, the structure was tested with static loads only and tested until failure

Predicted displacements and total static loading after instantaneous removal of center column

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1/8th Model Frame

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Full Size 2-D Exterior Frame

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1/8th Scale Model of 2-D Exterior Frame

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SAP2000 1/8th Scale Analytical Model

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1/8th Scale Cross-sections

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Maximum Deflection of Frame

Used SAP2000 Analysis for Deflection

Actual Results:

• Maximum - .21”

• Residual - .20”

Calculated Results:

• Maximum - .15”

• Residual - .08”

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Material Properties

Dimensions of scaled model are 1/8 of full scale model

Applied loads are 1/64 of full scale applied loading to maintain approximate equal amounts of stress as compared to full scale model

f’c = 7,000 psi

fy = 55 ksi, fu = 75 ksi

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XTract

Each cross section was modeled in XTract to determine moment-curvature behavior

Ultimate moment values from XTract were compared to moment values from SAP2000 full size analytical model

Confined concrete - Mander model

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SAP2000 Full Size Analytical Model

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Static Loading

1st Hinge – Reached Moment Capacity– Section B-B @ face of middle column – both sides– Load = 1015 lbs

Added pin at plastic hinge location – moment redistributed, checked deflection and curvature capacity

2nd Hinge – Reached Moment Capacity– Section B-B @ 6 ft. from face of column B – both sides– FAILURE– Load = 1454 lbs

Predicted Collapse Load = 1454 lbs Actual Collapse Load = 1800 lbs

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Collapse

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Predicting Collapse Improvements

Deflection– Correct dimensions of 1/8th scale frame– Calculation of Ic

Collapse Load– XTract – 1/8th scale cross-section moment-

curvature analysis